Various computer systems, such as electronic commerce (e-commerce) systems or network-based publication systems (e.g., eBay, Amazon, or Craigslist), which facilitate exchanges of items (e.g., goods or services) between users, may include many (e.g., millions or billions) of processes executing on one or more servers. Each of these processes may have one or more data inputs and one or more data outputs. Furthermore, input and output data in such systems may be non-stationary data. For example, data generated by a set of processes for a first locale may have statistical properties that vary from data generated by the same set of processes for a second locale. Given the complexity of such systems, determining their overall health may be well outside the purview of human operators.